Process of making cement



' Patented Apr. 5, 1927. I i I i I UNITED STATES PATENT OFFICE.

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- In a-copendm case,Se1-ialNo. ($6,110 then be subjected to a bum in g operation October 31, 1925, by myselzf and F. G; Kern, liter they can be d to a we have described and diimed a novel mode to o Portland of preparing slimctuml material such as cement. Insomecasesitisnotnecessajym bricks, books, as well as other molded the at burning, on, articles, from nw material although such operation is not precluded. largely of sea sand mixed with or less The blocks, etc, can he without finely divided calcium carbonate (say about c ushing if is des'med'to omit this step. as fine as ordinary sand)- In :ocordince The operation referred to at this 9 with the procedure of such prior applim Stagemay be conducted in a unnel kiln, say 05 tion, the naturally mixgd mfieriaL at I. of about 400 $0 500 0., containing preferably iron; about to b mp ures hdantially above 600 of calcium carbonate or calcareous material 0-, ld he v i ed so far as possible, in and from 40 to of such as sand order to leavefin the P10111101; about 15 is first calcined at. a low temperature sufli- 9 to. 11% 0f water. 70 cient to substantially decarbonatc the cal- Th0 p ti n f P sing he material ,cium carbonate pnsent, without producing a tunnel kiln for burning may reany sintering of the material. The material q me v l rs, in cco dance with the is then ground to a. fine powder, and is .hy l know}! Practlce of rning material in 20 dratcd by being mixed with water, in hilnsofthlscharaeter, whidiamwell known amount suificient to produce a stifi paste to be economical as regards incl. which can then be molded into blocks or The 1511011161 matelfiflh t P BVi H v other shapes, bricks, tiles and the like, the flushed 110i? is the]! ground to fine said materials thereafter subjected to P f Prefemhl of abou the fineness 0f 25 an induration treatment l ar-the action of ry Pfl flan cement {say until about steam or carbon dioxide or both preferably Q to 0f h crushed 1 11 ll pass under a pressure of say :25 atmospheres, unthrough 3 h g 610th 00 mshes til the hardened bl are completely indu P 1111931 m lrated and cured. The burned product upon analysis 30 Th raw t i l fi j i ti b found to consist of a combination of fore calcination or both, can be subjected to l ium hydroxide, calcium monosilicate and a washing operation if desired to remove 63143111131 h t s and P y also some soluble salts, and the calcined material may tilcalcllm} slhmfe- -contain for instance 60% of lime, 25% of Using the m n he Or inary proili 5% of lu i i th f f cedures well known In the Portland cement clay or partially decomposed feldspathic art can be p y n the ina y i ro k) 3% of ma i d th lik mulas for Portland cement mixtures can be I have found by experimentation, that the generally followfidmolded articles produced in accordance with It l e nd rs d that the process of 10 the said prior application can serve as a raw milkingcelllent ill e the S me, Whether the material for the production of hydraulic 1 1' i e men ha been conducted cement of good quality. The making of 09- with gasescontaining carbon dioxide, or ment' as will bereadily understood furnishes i h st am containing no appreciable a convenient outlet for any molded articles amount of Carbon dioxide, with mixtures v 45 whichbecome mis-shapen or broken or of'such two kinds of gases. This fact is becracked or otherwise damaged in the manulieved to be q 'te unexpected in view of the facture of the blocks. a fact that the temperature stated is below Th blocks, prepared as in ac o dan that at which the decarbonation of calcium with the disclosure of the said copending ap- Carbonate is complete or even substantially 5 'plication, a brief description of which proccomplete.

css has been given above, can if desired first V I claim be crushed or broken up more or less, say in- 1. A. rocess of making cement which comto fragments from the size of peas up to the prises molded articles from size of goose eggs, using-any suitable mamixtures of calcareous and siliceous matechinery for the purpose, and the bodies can rials, indurating such molded articles under steam pressure, hurnin the same at about made from a. natural mixture of calcareous 400 to 600- C., and r ucing to a fine powand siliceous material by calcining at a temder. perature too low to produce any substantial 5 comprises indurating sand-lime molded mixwith enough water to leave a. moldable mass, tules, under steam pressure, thereafter burnmolding, indurating under pressure at steam ing at a ut 400 to 600 C., and thereafter heat. pulv 3. A process which comprises burning inture.

1 durated sand-lime shaped products, at about 2. A process of making cement which amount of sintering, pulvei-izing, slaking In testimony whereof I aflix my signs- 400 to 600 C., said shaped products being LUDWIG KERN. 

